DISEASE CHARACTERISTICS:

• Diagnosis of colorectal adenocarcinoma

  • Metastatic disease
• Not curable by surgery or amenable to radiotherapy with curative intent

• Measurable disease

  • Patients with only lesions measuring ≥ 1 cm but < 2 cm must use spiral CT scan for pre- and post-treatment tumor assessments
• No known CNS metastases or carcinomatous meningitis

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• ECOG 0-2

Life expectancy

• At least 12 weeks

Hematopoietic

• Absolute neutrophil count ≥ 1,500/mm^3
• Platelet count ≥ 100,000/mm^3

Hepatic

• AST ≤ 5 times upper limit of normal (ULN)
• Bilirubin ≤ 0.5 mg/dL above ULN

Renal

• Creatinine ≤ 1.5 times ULN OR
• Creatinine clearance ≥ 60 mL/min

Cardiovascular

• No unstable angina
• No symptomatic congestive heart failure
• No serious uncontrolled cardiac arrhythmia

Pulmonary

• No prior clinical diagnosis of interstitial lung disease

Other

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• No active or uncontrolled infection
• No other concurrent serious illness
• No pre-existing paraesthesias/dysesthesias of ≥ grade 2 that would interfere with function
• No other malignancy within the past 5 years except adequately treated basal cell or squamous cell skin cancer or adequately treated noninvasive carcinomas

PRIOR CONCURRENT THERAPY:

Biologic therapy

• No concurrent sargramostim (GM-CSF)

Chemotherapy

• At least 6 months since prior adjuvant chemotherapy
• No prior fluorouracil for advanced colorectal cancer
• No prior adjuvant oxaliplatin
• No prior adjuvant irinotecan

Endocrine therapy

• Not specified

Radiotherapy

• No prior radiotherapy to > 25% of bone marrow

Surgery

• At least 4 weeks since prior major surgery